This invention relates generally to testing equipment, and in particular, to an environmental testing apparatus incorporating a vibration table wherein the climate within the compartment which houses the vibrators for the vibration table is controlled.
Many types of devices undergo testing to improve the quality and reliability of the devices. Typically, these types of devices undergo a series of environmental tests under various combinations of temperature, humidity, and other climatic conditions to insure product reliability and performance in extreme environmental conditions. Further, many of these devices undergo repetitive, shock vibration testing to insure that the devices are not adversely effected during normal operation.
In order to test their devices, manufacturers often utilize an environmental testing apparatus which is capable of producing rapid and extreme changes in temperature, humidity and other climatic conditions. A prominent designer and manufacturer of such environmental test apparatus is Thermotron Industries, Inc. of Holland, Mich. In operation, the devices to be tested are positioned within an environmental testing chamber in the testing apparatus wherein the devices are exposed to extreme climatic conditions.
Vibration testing is carried out by mounting the product to be tested upon some sort of platform or table which communicates with the environmental testing chamber and by then vibrating the table using any type of vibrator. Examples of a vibration table and the vibrators for vibrating the vibration table are shown in Wetzel et al., U.S. Pat. No. 5,804,732, assigned to the assignee of the present invention and incorporated herein by reference. Typically, in an environmental testing apparatus, the vibrators of the vibration table are positioned in a vibration compartment which is physically isolated from the environmental testing chamber. However, the vibrators in the vibration compartment are still partially exposed to the temperature extremes provided in the environmental testing chamber. As such, it is possible that the vibration means may be adversely effected, thereby reducing the efficiency of the vibration table. Further, exposing the vibrators to temperature extremes will lead to the expansion and contraction of the components of the vibrators during operation. This expansion and contraction of the components of the vibrators reduces the useful life of the vibrators and may cause leaks at the connections of the vibrators to a pneumatic source.
In order to minimize the effects of the temperature extremes within the vibration compartment, vents are often provided within the walls of the vibration compartment such that the interior of the vibration compartment communicates with the ambient air outside the environmental testing apparatus. By providing vents in the walls defining the vibration compartment, the noise external of the environmental testing apparatus is increased. Further, the vents in the walls allow particulate matter and moisture to enter the vibration compartment. Moisture within the vibration compartment has a tendency to penetrate and to freeze in the vibrators, thereby causing a decrease in the efficiency thereof. Heretofore, in order to prevent the moisture from freezing in the vibrators, dry-air or gaseous nitrogen was passed through the vibrators. This process of passing dry-air or gaseous nitrogen through the vibrators adds to the cost of the environmental testing apparatus. Therefore, it is highly desirable to eliminate this process while still preventing moisture from freezing in the vibrators.
Therefore, it is a primary object and feature of the present invention to provide a testing apparatus wherein the temperature within the compartment housing of the vibrators thereof is controlled.
It is a further object and feature of the present invention to provide a testing apparatus which discourages an accumulation of moisture within the vibrators thereof.
It is a further object and feature of the present invention to provide a testing apparatus which is simple to operate and less expensive to manufacture than prior testing apparatus.
In accordance with the present invention, a testing apparatus is provided for testing a product. The testing apparatus includes a testing cabinet which defines a first testing chamber and a vibration chamber. A vibration table has an upper surface communicating with the testing chamber and a lower surface. A plurality of vibrators are operatively connected to the lower surface of the vibration table and are disposed in the vibrator chamber. A climate control structure is provided for controlling the environment in the vibration chamber. The climate control structure includes a heating element communicating with the vibration chamber for heating the vibration chamber to a predetermined level. In addition, the climate controlling structure includes a cooling element communicating with the vibration chamber for cooling the vibration chamber to a predetermined level. A temperature sensor is positioned within the vibration chamber for sensing the temperature therein. A controller is operatively connected to the temperature sensor and to the heating and cooling elements. The controller controls the heating and cooling of the vibration chamber in response to the temperature sensed by the temperature sensor. It is contemplated that the vibration chamber be free from communication with the ambient air outside the testing cabinet.
In accordance with a further aspect of the present invention, a testing apparatus is provided for testing a product. The testing apparatus includes a testing cabinet defining a first testing chamber and a second vibration chamber. A vibration table has an upper surface communicating with the testing chamber and a lower surface. A plurality of vibrators are operatively connected to the lower surface of the vibration table and are disposed in the vibration chamber. A vibration chamber heating and cooling system communicates with the vibration chamber for maintaining the temperature in the vibration chamber at a predetermined level. In addition, a testing chamber heating and cooling system communicates with the testing chamber for varying the temperature in the testing chamber to predetermined levels.
The vibration chamber heating and cooling system includes a heating element communicating with the vibration chamber for heating the vibration chamber to a predetermined level. In addition, the vibration chamber heating and cooling system includes a cooling element communicating with the vibration chamber for cooling the vibration chamber to a predetermined level.
The testing apparatus also includes a temperature sensor within the vibration chamber for sensing the temperature therein. A controller is operatively connected to the temperature sensor and to the vibration chamber heating and cooling system. The controller controls the vibration chamber heating and cooling system in response to the temperature sensed by the temperature sensor. The controller may also be operatively connected to the testing chamber heating and cooling system for controlling the same. It is contemplated that the vibration chamber be free from communication with ambient air outside the testing chamber.
In accordance with a still further aspect of the present invention, an improvement is provided in the testing apparatus for testing a product. The testing apparatus includes a testing cabinet defining a first testing chamber for receiving the product therein and a vibration chamber; a vibration table having an upper surface communicating with the testing chamber and a lower surface; and a plurality of vibrators operatively connected to the lower surface of the vibration table and being disposed in the vibration chamber. The improvement includes providing a climate control structure communicating with the vibration chamber for controlling the environment therein.
The climate control structure includes a heating element communicating with the vibration chamber for heating the vibration chamber to a predetermined level. In addition, the climate control structure includes a cooling element communicating with the vibration chamber for cooling the vibration chamber to a predetermined level. A temperature sensor is positioned within the vibration chamber for sensing the temperature therein. A controller is operatively connected to the temperature sensor and to the heating and cooling elements for controlling the heating and cooling of the vibration chamber in response to the temperature sensed by the temperature sensor.